This invention relates to an improved flotation machine and cell design for the mining industry and, in particular for the process of separating minerals from ore through flotation of the mineral and removal from the ore.
In the mining industry, flotation is the primary method for concentrating and recovering minerals utilizing copper flotation, fine coal flotation, iron ore flotation, phosphate rock and potash flotation, base metal sulfide flotation and precious metal sulfide flotation.
Flotation is essentially a three phase unit process involving the intimate mixing of finely ground solids, liquids, and air to concentrate desired minerals from gangue by floating one away from the other. In carrying out the flotation process, the ore is crushed into finely ground solids and mixed with liquids to form a slurry or pulp. The slurry is then aerated using a flotation machine to achieve solid/liquid mixing and air dispersion through an internal air source or by a self-aspirating flotation machine. U.S. Pat. Nos. 4,425,232 and 4,800,017 describe a flotation separation apparatus and method comprising a flotation machine provided with a rotor-stator pump assembly submerged in a slurry and in which rotor blades agitate the slurry thoroughly mixing the solids and liquid and introducing air to the mixture for aeration and generation of froth or foam on the surface of the flotation cell. Particles of minerals attach to carrier air bubbles which are naturally buoyant and form the froth, this being the effective mechanism for mineral recovery. The froth is removed hydrodynamically from the top of the slurry mass together with the entrapped mineral particles which are recovered as froth is accumulated and dewatered.
Conventional cell tank designs as depicted in FIG. 1, labelled prior art, are rectangular or U-shaped and use a long froth overflow launder and partition plates. The froth overflow launder is generally longitudinally placed along side the tank, though some designs make use of a cross launder along the partition plate. Froth containing the desired minerals, which has risen with the air bubbles created by the rotor or mixer, overflows onto the launder and runs into a discharge pipe for collection.
Prior tank and overflow launder designs have proved inefficient and costly. The reinforced rectangular tank design contains corners and flat sides which must be heavily reinforced against bulging forces. Further, corners which exist in the rectangular design promote waste due to eddy currents and/or stagnant pockets. Launders are built independent from the flotation tanks and are often self-supporting.
It is an object of this invention to produce an economical cell and froth overflow launder design which provides a high ratio of froth overflow lip length to cell tank volume, with less troublesome cross launders. Cross launders provided in the prior art interfere with flow patterns and encroach on useful flotation volume.
It is a further object of this invention to produce a flotation cell and froth overflow launder design wherein the flotation tank volume is fully utilized due to the elimination of all corners.
Further, it is an object of this invention to produce a flotation cell and overflow froth launder design that can be arranged to maximize building floor space and thereby minimize costs.
This invention is directed to these objectives and others with specific reference to flotation equipment.